Compounds with a musk fragrance are sought-after components in the perfume industry. They are characterized both by their property of imparting an aura to perfume compositions and also by their ability to act as a fixer. Thus, musk fragrances are nowadays used in many perfume compositions.
The synthesis of biodegradable compounds with a musk fragrance has gained substantially in importance in recent years, since the synthetic musk compounds of the nitro-aromatic and polycyclic series are persistent and lipophilic, so that these compounds accumulate in aquatic food chains and fatty tissue (H. Brunn, G. Rimkus, Ernährungs-Umschau 1996, 43, 442 to 449; H. Brunn, G. Rimkus, Ernährungs-Umschau 1997, 44, 4 to 9). In order to close the gap, macrocyclic musk fragrances that are similar to natural compounds and are characterized by a macrocyclic ring with 13 to 17 C atoms, which has a ketone or an ester as functional group, have been developed to an increasing extent.
Furthermore, U.S. Pat. No. 5,166,412 discloses compounds of type (II)
where R1 is a C1 to C3 alkyl group and R2 is an H or a methyl group. These compounds are characterized by a musk fragrance that is associated with ambergris and fruity aspects.
In addition, WO-A 00/14051 shows that esters of type (III)

where R1 is a C1 to C4 alkyl or alkylene group and X is an oxygen, a methylene or ethylene group, also have a musk fragrance, the ambergris and fruity aspects being further in the background.
The aim was now to find compounds which, on the one hand, have a musk fragrance and in addition, by means of further original fragrance aspects, expand the range of raw materials available for the composition of perfumes.